The investigational regimen of an antiandrogen (flutamide), an aromatase inhibitor (letrozole), and reduced hydrocortisone dose vs. conventional treatment was shown short-term (2 year) to normalize linear growth rate and bone maturation. A prospective long-term randomized parallel study to adult height of an antiandrogen (flutamide) and an aromatase inhibitor (letrozole), and reduced hydrocortisone dose vs. conventional treatment is being completed. Patients that dropped out or were lost to follow-up are now being contacted to return to the NIH Clinical Center in order to obtain an adult height measurement. In a separate study, Abiraterone, an irreversible inhibitor of 17 hydroxylase/C17,20-lyase (cytochrome P450c17 CYP17), a key enzyme required for testosterone synthesis, is being studied in a multicenter Phase 1/2 study in pre-pubescent children.